Showing papers on "Wavelength-division multiplexing published in 1985"
TL;DR: In this article, the principles and features of six polarization state control schemes have been reviewed, including two new attempts, one using Faraday rotators and the other using rotatable fiber cranks.
Abstract: In heterodyne or homodyne optical fiber communications, the fluctuation of the polarization state in the fiber may deteriorate the receiver sensitivity. This paper reviews the principles and features of six polarization-state control schemes so far proposed, including two new attempts, one using Faraday rotators and the other using rotatable fiber cranks (RFC's), both of which have been proposed very recently. Experiments simulating actual optical heterodyne receivers are also described.
228 citations
TL;DR: It is shown that, in the synchronous case, the maximal error-free multiplexity is, in practice, N + 1, and, theoretically, the error probability of the system is analyzed and verified with experimental data.
Abstract: This paper describes a transmission system that uses passive optical multiplexing with gold sequences. The system is composed of an optical fiber network and electrical matched filters, and allows for N + 2 asynchronous stations each with a gold sequence address of length N . We analyze, theoretically, the error probability of the system and verify the results with experimental data. We further show that, in the synchronous case, the maximal error-free multiplexity is, in practice, N + 1 . The features of the System are as follows: 1) The system uses optical multiplexing instead of conventional electrical multiplexing. 2) The number of assignable addresses is large. 3) In the asynchronous case, each station can transmit a code at any time irrespective of other stations' timings.
93 citations
TL;DR: In this paper, the first single-fibre lightwave transmission system with more than 1 Tbit km/s capacity was described, which was achieved by closely spaced wavelength division multiplexing of ten distributed feedback lasers.
Abstract: We describe the first single-fibre lightwave transmission system with more than 1 Tbit km/s capacity. The ultrahigh-capacity transmission over 68.3 km of low-loss single-mode fibre was achieved by closely spaced wavelength division multiplexing of ten distributed feedback lasers. The lasers operated around 1.5 μm wavelength and the multiplexer channel spacing was 1.35 nm. Each laser/channel was modulated at 2 Gbit/s giving a total transmission capacity of 1.366 Tbit km/s.
81 citations
TL;DR: In this paper, a multiplexer and demultiplexer built from discrete GaAs FET's, a directly modulated distributed feedback laser, and a low capacitance avalanche photodiode receiver were used to achieve transmission at 4 Gbit/s over 103 km of single-mode optical fiber at 1.54 μm.
Abstract: Using a multiplexer and demultiplexer built from discrete GaAs FET's, a directly modulated distributed feedback laser, and a low capacitance avalanche photodiode receiver, we have achieved transmission at 4 Gbit/s over 103 km of single-mode optical fiber at 1.54 μm.
68 citations
TL;DR: In this article, design rules for overcoming the effects of optical crosstalk between digital PCM channels, when introducing wavelength-division-multiplexed (WDM) operation into optical-fiber systems are given.
Abstract: Design rules are given for overcoming the effects of optical crosstalk between digital PCM channels, when introducing wavelength-division-multiplexed (WDM) operation into optical-fiber systems. Power penalties are derived for two-, three-, and four-channel symmetric systems in the presence of interchannel interference, using a simple model for the recovery of the eye opening at a digital regenerator. The model is also extended to give a generalized, deterministic solution for the power penalties in asymmetric multichannel WDM systems, and the limitations of the model are discussed.
51 citations
TL;DR: In this paper, a guided-wave optical waveguide-division multi/demultiplexer for bidirectional transmission at (0.81 μm, 1.2 μm)/(0.89 μm and 1.3 μm) wavelengths has been realized using high-silica channel waveguides on silicon substrate.
Abstract: A guided-wave optical waveguide-division multi/demultiplexer for bidirectional transmission at (0.81 μm, 1.2 μm)/(0.89 μm, 1.3 μm) wavelengths has been realised using high-silica channel waveguides on silicon substrate. The multi/demultiplexer connected with graded-index multi-mode fibres shows a loss of 3.5−5 dB together with far-end and near-end crosstalk levels less than −30 dB and −50 dB, respectively.
34 citations
TL;DR: In this article, a 1.3-μm 1.1 km-long singlemode fiber-optic link with a 4.1-4.7 GHz frequency response has been developed.
Abstract: A 1.3-μm 1.1-km-long single-mode fiber-optic link with a 4.1-4.7 GHz frequency response has been developed. This is one of the highest freqUency fiber-optic links reported to date. A 60-dB SNR, ±1.0-dB gain flatness, and 44-dB spur-free dynamic range was observed. The performance of this link is primarily determined by the direct-modulated laser transmitter. This paper discusses the design of that component along with the development and performance of the complete fiber-optic link.
31 citations
TL;DR: In this paper, a grating multiplexer in Littrow-configuration is presented, whose passband width normalized to channel spacing is comparable with grating demultiplexers.
Abstract: A grating multiplexer in Littrow-configuration is presented, whose passband width-normalized to channel spacing-is comparable with grating demultiplexers. As shown by calculation, a wide passband is attainable by very small input fiber spacing. Using a standard-( 50/125 \mu m)-GI-fiber as transmission fiber, a 1-dB pass-band of 30 nm with a channel spacing of 46 nm is achieved in an 8- channel device. The insertion losses for each channel are in the range 1.4-2.5 dB for 8- or 10-channel devices.
29 citations
TL;DR: In this article, a four-channel multimode transmission subsystem employing wavelength division multiplexing (WDM) was assembled and optically evaluated for both multiplexer/demultiplexer (Mux/Demux) pair.
Abstract: A four-channel multimode transmission subsystem employing wavelength division multiplexing (WDM) was assembled and optically evaluated. Diffraction grating devices with identical fibers for inputs and outputs were used for both multiplexing and demultiplexing. The 1-dB full width of the passbands was ∼4 nm thus there was a requirement for wavelength selection and temperature tuning of the corresponding laser sources. A temperature excursion of 7°C from the optimum resulted in 1 dB of additional attenuation. Insertion losses for the multiplexer/demultiplexer (Mux/Demux) pair were 3.7, 3.6, 4.7, and 7.3 dB at 812, 830, 867, and 885 nm, respectively. The higher losses at 867 and 885 nm were due to chromatic abberation. The channel spacing of 18 nm is smaller than could be achieved with state-of-the-art filter devices. For unidirectional transmission the out of band rejection exceeded 40 dB in all channels.
28 citations
TL;DR: In this paper, a broadly tunable (85 A/V) wavelength-selective Ti: LiNbO3-waveguide directional coupler is presented, with which the authors demonstrate λ=1.3 μm/λ = 1.55 μm multiplexing while simultaneously modulating the long-wavelength channel.
Abstract: We report a broadly tunable (85 A/V) wavelength-selective Ti: LiNbO3-waveguide directional coupler, with which we demonstrate λ=1.3 μm/λ = 1.55 μm multiplexing while simultaneously modulating the long-wavelength channel.
21 citations
11 Feb 1985
TL;DR: In this article, the authors used a multiplexer and demultiplexer built with discrete GaAs FETs to demonstrate 4 Gb/s operation over 103 km of singlemode optical fiber.
Abstract: We have conducted an experiment which demonstrates 4 Gb/s operation over 103 km of single-mode optical fiber. Previous transmission experiments have been limited to about 2 Gb/s [1,2,3], in part because this is the highest bit rate for which commercial error-rate measuring equipment is available. We have used a multiplexer and demultiplexer built with discrete GaAs FETs to generate a 4 Gb/s NRZ tat pattern from a 2 Gb/s pseudorandom sequence, and to recover 2 Gb/s for error-rate measurements from the 4 Gb/s receiver output. The 4 Gb/s pattern was used to directly modulate a 154 μm vapor phase transported buried heterostructure (VPTBH) distributed feedback laser [4].
Patent•
22 May 1985
TL;DR: In this paper, a demultiplexer for systems in optical fiber, that can also be used as a multiplexer without requiring any particular modifications, is described, where an input optical fiber bearing multiple-input multiple-output (MIMO) signals and n output optical fibers are connected to the MIMO.
Abstract: A demultiplexer for systems in optical fiber, that can also be used as a multiplexer without requiring any particular modifications, is described. An input optical fiber, bearing multiplexer signals, and n output optical fibers, are connected to the multiplexer. (n-1) pairs of identical optical filters are installed along the course of the light rays inside the device: the signals that cross the filters of each pair that are met first by the light ray coming from the input optical fiber are output to the first (n-1) output optical fibers; the signal reflected by the other fitter of the (n-1)-th pair is output to the n-th output optical fiber.
TL;DR: In this paper, the design options for such systems are discussed, followed by a description of five laboratory trials: a dispersion-limited 176-km 34-Mbit/s experiment, employing commercial components throughout; two loss-limited system trials over 220 km at 140 Mbit/sec and 233 km at 34 Mbits/sec; and a further two experiments over 223 and 251 km at the same line rates, featuring single line DFB lasers and step-index monomode fiber.
Abstract: Long-haul optical fiber transmission system experiments have been carried out over unrepeatered spans up to 250 km. In this paper the design options for such systems will be discussed, followed by a description of five laboratory trials: a dispersion-limited 176-km 34- Mbit/s experiment, employing commercial components throughout; two loss-limited system trials over 220 km at 140 Mbit/s and 233 km at 34 Mbit/s, based on multimode lasers and dispersion-shifted fiber; and a further two experiments over 223 and 251 km at the same line rates, featuring single-line DFB lasers and step-index monomode fiber.
11 Feb 1985
TL;DR: In this paper, the results of a ten-channel WDM system operating at 1.5-μm wavelength were reported with 68.3 km of fiber and with a channel spacing and data rate of 1.35 nm and 2 Gbit/sec.
Abstract: Although recent fiber-optic transmission experiments have shown impressive results in unrepeatered transmission distance at high data rates,1,2 only a small fraction of the information carrying capacity of the optical fiber has been utilized. To utilize fully the fiber bandwidth, it is desirable to use many closely spaced wavelength division multiplexed (WDM) channels in the minimum loss region ~1.5 μm. We report here the results of a ten-channel WDM system operating at 1.5-μm wavelength. The system was tested with 68.3 km of fiber and with a channel spacing and data rate of 1.35 nm and 2 Gbit/sec, respectively. The experimental setup is shown in Fig. 1. The lasers employed in this experiment were HRO distributed feedback (DFB) lasers.3 The pure single-longitudinal-mode operation, even under high-speed modulation, of these lasers was essential for achieving the narrow channel spacing, low cross talk, and error-free (<10−9-BER) operation. The laser wavelengths were between 1.529 and 1.561 μm and selected from several wafers with different design wavelengths.
TL;DR: A passive, unswitched scheme for directly interconnecting N stations, each of which has C transmitters and receivers, which outperforms standard topologies with C parallel buses in two respects: the aggregate throughput is proportional to C rather than to C and the power of each transmitter need reach only N/C, instead of N, receivers.
Abstract: A passive, unswitched scheme is introduced for directly interconnecting N stations, each of which has C transmitters and receivers. Implementations using fiber optics with spatial multiplexing and optionally wavelength multiplexing are discussed. This scheme utilizes the same resources as standard topologies with C parallel buses but outperforms them in two respects: (1) the aggregate throughput is proportional to C squared rather than to C; and (2) the power of each transmitter need reach only N/C, instead of N, receivers.
11 Feb 1985
01 Jan 1985
TL;DR: In this paper, a new multiplexer/demultiplexer structure with tunable center wavelength and a bandwidth between several nm to 100 nm on InP by varying waveguide dimensions was proposed.
Abstract: We propose a new multiplexer/demultiplexer structure with tunable center wavelength and a bandwidth between several nm to 100 nm on InP by varying waveguide dimensions.
TL;DR: In this article, the principles and features of six polarization state control schemes have been reviewed, including two new attempts, one using Faraday rotators and the other using rotatable fiber cranks.
Abstract: In heterodyne or homodyne optical fiber communications, the fluctuation of the polarization state in the fiber may deteriorate the receiver sensitivity. This paper reviews the principles and features of six polarization-state control schemes so far proposed, including two new attempts, one using Faraday rotators and the other using rotatable fiber cranks (RFC's), both of which have been proposed very recently. Experiments simulating actual optical heterodyne receivers are also described.
Journal Article•
NEC1
TL;DR: InGaAsP 1.3-μm LEDs are reliable inexpensive alternatives to laser diodes in intermediate range optical communication systems such as local area networks and subscriber loops.
Abstract: InGaAsP 1.3-μm LEDs are reliable inexpensive alternatives to laser diodes in intermediate range optical communication systems such as local area networks and subscriber loops. High-power LEDs with a high modulation bandwidth are very attractive sources for these systems. However, it has been very difficult to achieve these two performances simultaneously because of power-bandwidth trade-offs.1,2 The highest reported power launched into 50-μm core 0.20-N.A. graded-index (Gl) fiber was 50-80 μW with a 50-100-MHz modulation bandwidth.1
11 Feb 1985
TL;DR: Over the last ten years, numerous innovations in the field of fiber-optic technology have resulted in the introduction of trunk transmission systems that can provide various broadband information services because of Fiber-Optic well-known features.
Abstract: Over the last ten years, numerous innovations in the field of fiber-optic technology have resulted in the introduction of trunk transmission systems. In the near future, the prices of optical fibers are expected to decrease considerably. Consequently, many organizations are now studying the feasibility of fiber-optic subscriber loops that can provide various broadband information services because of fiber-optic well-known features.
21 May 1985
TL;DR: In this article, the authors proposed a WDM-based multigigabit per second (MIMO) system with a 10−9 error probability for a single-mode optical fiber.
Abstract: The transmission bandwidth of a single-mode optical fiber is Immense. For example, at the wavelength of minimum dispersion (λ ≃1.3 μm) it is possible in theory to send a 100-Gbit/sec signal over a 100-km fiber with a 10−9 error probability.1 Furthermore, wavelength-division-multiplexing (WDM) techniques can be used to increase the total Information-carrying capacity of a fiber almost without limit. To explore this vast information capacity, lightwave research is driven to make available fibers, lasers, photodetectors, and other components that satisfy the stringent requirements for multigigabit per second transmission. System experiments are conducted to demonstrate feasibility and provide understanding of how device behavior affects system performance.
TL;DR: General guidelines for avoiding serious microbending loss in this type of cable structure are reviewed, and different methods of implementing the design principles are demonstrated by way of discussions specific to the three electrooptic core designs that were manufactured.
Abstract: The design, manufacture, and testing of three armored fiber optic tow cables is discussed. The motivation for these developments was the technical need to have low-loss high-bandwidth transmission lines, that function with negligible crosstalk and absence of ground loops, placed within the limited core space of the cable. General guidelines for avoiding serious microbending loss in this type of cable structure are reviewed, and different methods of implementing the design principles are demonstrated by way of discussions specific to the three electrooptic core designs that were manufactured. A discussion is given regarding some of the practical problems associated with manufacturing. For two of the cable designS, measurements of optical attenuation with a Tektronix model 150 optical time-domain reflectometer are presented for several stages of manufacture, and approximate changes in attenuation are given for a tension loading of 33kN.